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Community Member

Weird static problem

We have a QSIG PRI connecting a Nortel Option 81C and a CallManager 4.1(3) system. When I call from my IP phone to a Nortel phone that hangs off of the PBX, I hear static in my phone when I talk. It goes away as soon as I stop talking. The person on the Nortel phone doesn't hear any static at all, and they sound clear as a bell to me. The static only happens on my end when I'm talking.

I don't even know where to begin troubleshooting this problem.

Any thoughts?

Thanks,

John

4 REPLIES
Community Member

Re: Weird static problem

Hi John,

This type of issue happens usually due to VAD or if it is not adjusted properly. Cisco usually recommends disabling VAD if fine tuning does not help. Please use the following link to tune or turn off VAD.

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a00800a9982.shtml

Let me know how it goes.

Regards,

Subhrojyoti

Community Member

Re: Weird static problem

We don't even have VAD turned on. At least I don't think we do. I sure didn't turn it on, but I guess I should make sure that someone else didn't accidentally turn it on.

EDIT: I just verified that we do not have silence suppression turned on.

Any other ideas?

Thanks!

John

Silver

Re: Weird static problem

VAD is enabled on voip dial peers by default. You need to disable it explicitly with the "no vad" command under the dial peer config.

HTH

Community Member

Re: Weird static problem

This is CCM with MGCP gateways, not CME. We're not using dial peers.

Interestingly, I've discovered that this only happens when I call a certain extension that has appearances on two different phones in the same room. It doesn't not happen when I call other Nortel phones, so it must have something to do with that room. I also hear an quiet electronic hum on one of those phones. There's probably just something weird about those two phones.

I'm not going to worry about this any longer unless the problem starts happening on other phones.

Thanks,

John

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